Wireless telecommunication systems are well known in the art. In order to provide global connectivity for wireless systems, standards have been developed and are being implemented. One current standard in widespread use is known as Global System for Mobile Telecommunications (GSM). This is considered as a so-called Second Generation mobile radio system standard (2G) and was followed by its revision (2.5G). General Packet Radio Service (GPRS) and Enhanced Data Rates For GSM Evolution (EDGE) are examples of 2.5G technologies that offer relatively high speed data service on top of 2G GSM networks. Each one of these standards sought to improve upon the prior standard with additional features and enhancements. In January 1998, the European Telecommunications Standard Institute—Special Mobile Group (ETSI SMG) agreed on a radio access scheme for Third Generation Radio Systems called Universal Mobile Telecommunications Systems (UMTS). To further implement the UMTS standard, the Third Generation Partnership Project (3GPP) was formed in December 1998. 3GPP continues to work on a common third generational mobile radio standard.
A typical UMTS system architecture in accordance with current 3GPP specifications is depicted in FIG. 1. The UMTS network architecture includes a core network (CN) interconnected with a UMTS Terrestrial Radio Access Network (UTRAN) via an interface known as an Iu which is defined in detail in the current publicly available 3GPP specification documents. The UTRAN is configured to provide wireless telecommunication services to users through wireless transmit/receive units (WTRUs), also known as User Equipments (UEs) in 3GPP, via a radio interface known as a Uu. The UTRAN has one or more Radio Network Controllers (RNCs) and base stations, known as Node Bs in 3GPP, which collectively provide for the geographic coverage for wireless communications with WTRUs. One or more Node Bs are connected to each RNC via an interface known as an Iub in 3GPP. The UTRAN may have several groups of Node Bs connected to different RNCs; only two are shown in the example depicted in FIG. 1. Where more than one RNC is provided in a UTRAN, inter-RNC communication is performed via an Iur interface, also defined in 3GPP specifications.
Communications external to the network components are performed by the Node Bs on a user level via the Uu interface and the CN on a network level via various CN connections to external systems.
In general, the primary function of base stations, such as Node Bs, is to provide a radio connection between the base stations' network and the WTRUs. Typically a base station emits common channel signals allowing non-connected WTRUs to become synchronized with the base station's timing. In 3GPP, a Node B provides the physical radio connection with the WTRUs. The Node B receives signals over the Iub interface from the RNC that controls the radio signals transmitted by the Node B over the Uu interface.
A CN is responsible for routing information to its correct destination. For example, the CN may route voice traffic from a WTRU that is received by the UMTS via one of the Node Bs to a public switched telephone network (PSTN) or packet data destined for the Internet (not shown for purposes of simplicity). In 3GPP, the CN has six (6) major components: 1) a serving General Packet Radio Service (GPRS) support node (SGSN); 2) a gateway GPRS support node (GGSN); 3) a border gateway; 4) a visitor location register (VLR); 5) a mobile services switching center; and 6) a gateway mobile services switching center. The serving GPRS support node (SGSN) provides access to packet switched (PS) domains, such as the Internet. The gateway GPRS support node (GGSN) is a gateway node for connections to other networks. All data traffic going to other operator's networks or the Internet goes through the GGSN. The border gateway acts as a firewall to prevent attacks by intruders outside the network on subscribers within the network realm. The visitor location register (VLR) is a current serving networks ‘copy’ of subscriber data needed to provide services. This information initially comes from a database which administers mobile subscribers. The mobile services switching center is in charge of ‘circuit switched’ connections from UMTS terminals to the network. The gateway mobile services switching center implements routing functions required based on current locations of subscribers. The gateway mobile services switching center also receives and administers connection requests from subscribers from external networks.
The RNCs generally control internal functions of the UTRAN. The RNCs also provide intermediary services for communications having a local component via an Iub interface connection with a Node B and an external service component via a connection between the CN and an external system, for example, overseas calls made from a cell phone in a domestic UMTS.
Typically, an RNC oversees multiple base stations, manages radio resources within the geographic area of wireless radio service coverage serviced by the Node Bs and controls the physical radio resources for the Uu interface. In 3GPP, the Iu interface of an RNC provides two connections to the CN: one to a packet switched (PS) domain and the other to a circuit switched domain. Other important functions of the RNCs include confidentiality and integrity protection.
In communication systems such as Third Generation Partnership Project (3GPP) Time Division Duplex (TDD) and Frequency Division Duplex (FDD) systems, multiple shared and dedicated channels of variable rate data are combined for transmission. Background specification data for such systems are publicly available and continue to be developed.
Radio Access Bearer Managers (RABMs) and Packet Data Convergence Protocol (PDCP) processes are known for 3GPP systyems. The present invention recognizes the desirability of combining these functions in a single component, particularly for mobile WRTUs.